This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Our aim is to test 3 hypotheses: 1)PET imaging shows highest FDDNP concentrations in AD-affected brain regions in AD patients, intermediate concentrations in MCI, and lowest in age-matched controls. 2)FDDNP-PET and FDG-PET imaging patterns are inversely correlated. 3)Subjects with APOE-4 have greater FDDNP brain concentrations than those without this genetic risk for AD. These studies may eventually provide a safe, effective, and practical means for 1) early presymtomatic diagnosis, and 2) monitoring disease progression and efficacy of novel pharmacologic interventions.